It was eerily dark in the village of Ponyville, with only a few faint stars overhead providing the barest hinting of light. The moon was nowhere to be seen, which was highly unusual, reflected the pony taking advantage of the lack of illumination.

Using all her stealth and cunning, the figure crept through the streets of Ponyville, darting from pool of darkness to a wall of bushes, before pausing behind an empty cart left carelessly in the marketplace.

It was unlikely that anyone would see her in the faint, early hours of the morning, but this pony had taken no chances. Her mane and tail were tightly wrapped into buns, and were covered in dark cloth. Her face and horn were smeared with now-dried mud, and her cutie mark had been carefully concealed with a quick application of magic.

From the cart, it was a quick dash to the next hiding spot. This continued for nearly an hour, the normally ten-minute walk lengthened greatly at this reduced pace, but despite a few close calls by ponies out at abnormally late/early times, the clever mare was not spotted.

"Here goes " she mumbled, around a gleaming object clenched in her teeth, as her horn began to softly glow (though the light was muted by the mud encrusting it.)

A flash of light, and she was gone only to reappear instants later in main room of the Sugarcube Corner. After a hasty (and slightly panicked) examination of the room, she determined that her entrance had not been noticed, and she crept silently up the stairs and into a certain pink pony's room.

The knife glistened in her jaws.

"I'm sorry, Pinkie," Twilight Sparkle whispered as she gripped the handle tighter with her mouth, "but I can't let you go through with it," and with that, she plunged the knife into her target.

"Aw, come on, Twilight! It's your birthday party! What if I only invite everyone in Ponyville?"

Twilight looked at her somewhat scatterbrained friend oddly.

"As opposed to ?"

"Oh, everyone in Equestria. See? I already have all the invitations made out!" And with that, the pink pony thrust a list in front of her brainy friend.

Twilight scanned the list, marveling at how very many ponies actually existed.

"All our friends, Cherilee, Big Mac, the Cutie Mark Crusaders, Zecora, Snips and Snails- why would you invite them?- Trixie, Gilda, Doctor Whooves, Derpy- Fluttershy's Rabbits? That dragon we faced on the mountain? THE COCKATRICE? The Wonderbolts? The Mayor? Pinkie, I don't know who a lot of these people are, and some of them have tried to kill me. Why would you invite them?"

Pinkie smiled, and a look of total confidence washed over her face.

"I do not know! I just wanted to make people happy, and parties make people happy, with singing and dancing and cupcakes and sweets and OMIGOSH do you think that rabbits can eat frosting 'cuz I don't want to make Fluttershy's bunnies sick "

"Pinkie! I'm telling you, I really don't want a big party. Just you, and me, and Apple Jack and Rarity and Spike and Fluttershy and Rainbow Dash. Just us. Would that be okay? Please?"

Still, over the next few weeks, Twilight had noticed inevitable signs that a category-five party was beginning to brew in her friend's head, and the signs were getting progressively harder to explain away as an innocent action. Twilight had helped the Cakes to carry large amounts of purple and magenta frosting from a shipment received from Fillydelphia, which was only the first outward sign that a major party was brewing.

Twilight noticed that all around town, ponies would suddenly stop talking as soon as she approached. Many people were giggling at her behind her back. Spike was goofing off much more than usual, Fluttershy had been teaching her birds to sing a tune that sounded suspiciously like "Happy Birthday," and ponies all over town seemed to have some sort of excuse to be busy on Twilight's birthday.

For all Twilight had discovered about friendship, she was still fairly socially awkward, and just wanted to spend some time with her friends. Not to mention that it would be her first birthday away from home in Canterlot, and it was something of a big deal for her.

So there was only one option that Twilight Sparkle could see: she would have to sabotage Pinkie Pie's party.

"Wha how wha " Twilight stuttered, trying desperately to figure out what had just happened.

"Oh, oh, let me explain, let me explain!" chanted Pinkie, who had somehow come downstairs in record time. "I wanted you to have a big party, but you were being a party pooper and all like 'Nuh-Uh,' and I was all like 'Yah huh!' So then today my Pinkie Sense started making me twitch and jitter and I knew it meant something really really important. And then I figured out that it meant that you were going to break in and try to sabotage my party!"

"Wait, your Pinkie Senses told you that."

"Yup!"

"Exactly that."

"Yup!"

" If it wasn't for evidence to the contrary, I'd still think you're a liar."

"Probably, but that wouldn't be as much fun."

"Come now, Twilight Sparkle, we are about to play 'Pin the tail on the Pony, and quite frankly, I'm on a winning streak," Celestia boasted as she pulled her student away from Pinkie.

The party continued for the rest of the night, through most of the day, and ended the following night. Technically, it was seven days long (Celestia and Luna should not have drinking contests. Ever), but still. A grand time and merriment were had by all.

After the party, during the massive clean-up effort, Twilight approached Pinkie.

"Pinkie, this really isn't easy for me-"

Pinkie interrupted her with a bear hug, causing Twilight to blush.

"Aw, you don't need to say it. I can see it in your eyes. You're welcome, it's what I'd do for any friend!"

Pinkie ended the embrace, and turned to see Twilight smirking at her.

"Okay, I will admit, that this was a lot of fun. And I'll admit that you were right and I was wrong." Twilight paused, levitating a camera. "But I will also admit that cameras are very useful, and you were definitely throwing yourself at a certain red earth pony What would Apple Jack say about that, I wonder "

Well, if we are to consider a "Day" to be "The period between the rising and setting of the sun," then yes, it was seven days... but really, it was only about 25 hours long. However, I'm thinking that getting the entities responsible for control of the motion of the sun and moon drunk is a bad idea, because I can totally see Celestia going, "Hey, look what I can do!" then whipping the sun through the sky as fast as she can.